How to Choose Solar collector for Swimming Pools?

solar heater swimming pool

Swimming pools are an ideal application for solar water heating, as the temperature required is quite low - under 30°C. Most installers will recommend flat plates to keep the price down - because the amount of panels required is much larger than for heating domestic hot water - however, if you can buy a high efficiency evacuated tube solar panel for the same money - you might as well enjoy solar heated pool water all year round - instead of just in July and August! If you used flat plates, a rule of thumb for calculating what you need is to fit the equivalent of 50% of the pool's surface area. For Vacuum tube panels, this is reduced to 25% - and of course, they will carry on working in the autumn, winter and spring. The SFB205818-AL panel is 2.52m2so each panel will heat 11m2of pool area. A 40m2pool would only need 4 SFB205818-AL panels. But the actual efficient is up to the different areas and the climate condition.  Installation is very simple. If you have chlorine you will need to fit a stainless steel heat exchanger (this is because chlorine causes copper to corrode). These are available from pool suppliers (they are needed for conventional heating methods for the same reason). If you don’t have chlorine, you can simply put the solar panel in-line with the pool filter, so that the pump directs water through the panel before returning it to the pool. As the panel will NOT radiate heat on cold days, heat losses will be confined to your pipe runs only - so you do not necessarily need a controller, although one can be fitted, to control a 3-way solenoid valve to divert the water through the panel when the panel is hotter than the pool water. We advice all pool owners to use a pool cover to reduce evaporation of water at night and when not in use (responsible for a BIG loss of heat). If the customer does not use a pool cover, they need to increase the solar panels to compensate. Lower night time temperatures =much higher loss of heat from evaporation. We don't really make any effort to account for insulation, indoor/outdoor situation of pool, as it is difficult to calculate, and often the customer doesn't know the details we need anyway.    

How many solar collectors do I need for swimming pool? As the power solar collectors can produce depends on sunshine,the solar insolation is a key factor.

Here are the figures: Insolation Levels (Canada) Average Insolation (10 year average) kWh/m2/day


State City Latitude Longitude Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Year Avg
AB Edmonton 53o 34' N 113o 31' W 1.45 2.36 3.41 4.25 4.91 5.42 5.55 4.76 3.52 2.18 1.43 1.21 3.37
BC Victoria 48o 25' N 123o 19' W 1 1.82 2.93 4.01 5.13 5.54 5.85 5.28 3.88 2.17 1.11 0.86 3.29
MB Winnipeg 49o 54' N 97o 14' W 1.21 2.08 3.27 4.55 5.54 5.8 5,85 4.84 3.32 2.21 1.33 1.02 3.41
NL St. Johns 45o 19' N 65o 53' W 1.56 2.27 3.48 4.19 4.76 5.05 5.05 4.54 3.53 2.29 1.43 1.27 3.28
NS Halifax 44o 39' N 63o 34' W 1.56 2.31 3.46 4.09 4.82 5.27 5.41 4.86 3.92 2.54 1.53 1.3 3.42
ON Toronto 43o 41' N 79o 38' W 1.44 2.27 3.19 4.13 5.15 5.83 5.67 4.82 3.66 2.47 1.48 1.2 3.44
QC Montreal 45o 28' N 73o 45' W 1.45 2.36 3.41 4.25 4.91 5.42 5.55 4.76 3.52 2.18 1.43 1.21 3.37
SK Regina 45o 19' N 65o 53' W 1.14 1.96 3.02 4.69 5.48 5.79 6.14 4.96 3.42 2.29 1.3 0.95 3.42

  figures are kWh/m2/day


The swimming pool sizing is quite easy. Suppoing we have a pool with 20m x 5m (=100m2). The area of the surface of the pool is much more important than the volume of water - as heat loss is mainly through the surface of the pool, and not through the side walls (the side walls are only very small area whereas the surface and base of the pool are very large areas).   For the area with solar insolation of 3.5kwh/m2/day, we aim to heat the pool using solar panels from Mar to Sep. Between Oct and Feb, there is not enough sunshine to heat the pool very well. We will suggest the collectors area reach to 25% of pool area (so for 100m2 pool, you would chose 25m2 of SFB solar panel), but this will not get the water really warm. If the customer has more money, then we recommend using 30-35%.For the area with solar insolation of 5kwh/m2/day,sunlight is 2 times stronger,so you can choose 15% of pool area.Also, the sunlight is much better spread, so you get almost the same amount from January to December. This means that you can easily heat a pool every day of the year in the city like Edmonton .   So for Canada, I would recommend a minimum of 15% (so a 5.5*11M=60.5m2pool requires 9m2SFB solar panels), and a maximum of 25% (so 60.5m2pool requires 15m2 SFB solar panels).      


solar heater swimming pool   



solar heater swimming pool